1. Field of the Invention
The invention relates to a paste extruder. Such machines are employed to produce profiled sections, in particular, from PTFE. In an extruder of this type, an extrusion barrel is seated on a machine frame, the extrusion barrel being connected to an extrusion die. With an extrusion piston of the extrusion barrel, a parison material comprised of PTFE powder is pressed out through an opening of the extrusion die which is shaped to correspond to the desired profile. By way of a subsequent conditioning process, the powdered material is sintered together to form a solid PTFE material. For the production of pipes, a mandrel rod is arranged coaxially in the extrusion barrel. On the front end of the mandrel rod facing the extrusion die, a mandrel tip is arranged which projects into the extrusion opening of the extrusion die and keeps open the interior chamber of a pipe.
2. Description of the Related Art
For the production of, in particular, thin-walled pipes, the problem arises that, during feeding with a parison material or a parison body, a time-consuming centering of the mandrel in the extrusion opening of the extrusion die must be carried out. It is furthermore problematic that, with rigid mandrel rods, the mandrel rod is deflected transversely to the axial direction because of different material densities, etc. of the parison body or due to geometric errors, thus resulting in varying wall thicknesses of the pipe, which is not desirable for obvious reasons.
On this basis, it is the object of the invention to propose a paste extruder wherein these drawbacks are circumvented.